Trapezium

(Astronomy)

The Trapezium, or Theta Orionis, is probably the best known multiple star in the sky. It can be observed even with a small telescope. It can be found inside M42, the Orion Nebula.

It (unsurprisingly) resembes a small Trapeze:

                        f
      h             C
                 .·' '·.      
              .·'       '·.         
           .·'             '·. 
        .·'            g     .:D
      A;                ..·''  
        '.         ..·''
     e    ''.  ,.·'
             'B

The stars A - D are the most luminous ones, C being the brightest in the group with a visual magnitude of 5.4, followed by D, with mag 6.3, then A at 6.8 and B, actually a binary star, at 6.5.

With a larger telescope one should be able to make out the neighboring stars (e - h) as well, although their magnitudes start at 11. (The stars e and f are often used by amateur astronomers to judge the quality of their telescopes.)

Tra*pe"zi*um (?), n.; pl. E. Trapeziums (#), L. Trapezia (#). [NL., fr. Gr. a little table, an irregular four-sided figure, dim. of a table, for ; (see Tetra-) + foot, akin to foot; hence, originally, a table with four feet. See Foot.]

1. Geom.

A plane figure bounded by four right lines, of which no two are parallel.

2. Anat. (a)

A bone of the carpus at the base of the first metacarpal, or thumb.

A region on the ventral side of the brain, either just back of the pons Varolii, or, as in man, covered by the posterior extension of its transverse fibers.

© Webster 1913.